Transfer systems or loaders, as they are commonly called, are used to automatically convey workpieces from one point to another in many industrial applications. One such application is the conveyance of workpieces from a supply stack or magazine to the clamping spindle of a grinding machine where a finish grinding operation is carried out. Because the workpieces are small and specifically configured, it is necessary that the loader precisely receive the workpiece from the magazine stack and carry it to the finishing station in a known orientation so as to permit the workpiece to be clamped and released for the finishing operation.
A specific application for the present invention as described herein is the automatic loading and grinding of carbide machine tool inserts which, as is well known to those skilled in the art, are small triangular, flat-sided objects which require finish grinding after firing. A commercially available grinder for performing grinding operations on carbide inserts is the universal insert grinder manufactured and sold by Wit-O-Matic, Inc. of Plymouth, Michigan and the loader herein described is readily adaptable for use on the Wit-O-Matic machine.
Prior art loaders are known; one example is the "Workpiece Feed Mechanism" described in the United States Patent to E. M. Newsome, U.S. Pat. No. 3,665,656. In that patent of mechanism for carrying carbide inserts from a magazine stack to a clamping spindle is described. The Newsome mechanism includes, among other things, a retractable workpiece slide (62 in the patent drawing) which supports a face of the insert while in the loader seat and which engages the clamping spindle to retract away from the insert when the loader reaches the clamping station. This mechanism adds to the cost and complexity of the machine and requires periodic maintenance for satisfactory operation. Moreover, the Newsome patent does not disclose a simple and easily operated mechanism for the fine adjustment of the position of the workpiece seat so as to ensure that each workpiece is precisely located therein prior to initiating the transfer from magazine stack to the clamping spindle.
A further problem of prior art devices such as Newsome arises from the fact that it is necessary to apply a bias to the end of the insert magazine stack so as to urge the inserts laterally toward and into the transfer mechanism seat. Accordingly, the face of the next insert to be transferred slides against the side of the transfer mechanism over its entire work stroke to and from the clamping station. The carbide inserts, because of their hardness and abrasive quality, thus produce wear on the side of the transfer mechanism, such wear being related to the bias pressure which is exerted on the workpiece stack to carry out the loading operation.